Behaviour of concrete with lightweight aggregates derived from E-waste

Abstract

Lightweight concrete is typically produced using lightweight aggregates, which are generally costlier than conventional crushed rock aggregates. Alternatively, aggregates may be derived from waste plastics. This paper presents a new method of developing lightweight aggregates from electronic waste (E-waste) scrap. This melted plastic aggregates (MPA) were produced by melting E-waste scrap, cooling the melt at ambient temperature, and breaking the resultant pellets to coarse aggregate size (10–20 mm). The chemical composition of both raw E-waste aggregate and MPA was determined through elemental analysis. Concrete mixes were prepared by replacing crushed rock aggregates (NA) with MPA at levels of 0, 33, 66, and 100 %, using three water-cement (w/c) ratios: 0.43, 0.47, and 0.53. Compressive strength was evaluated at 7, 28, and 56 days. Elastic modulus, flexural strength, and split tensile strength were assessed at 28 days. Ductility index under impact was also determined. The microstructure of the interfacial transition zone (ITZ) was examined using scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The performance of MPA concrete is compared with that of concrete containing other plastic aggregates such as PET, LDPE, and HDPE, as well as commercially available expanded polystyrene (EPS) beads. Based on the test results, an optimum replacement level is recommended that satisfies the specifications for structural lightweight concrete (ACI 318, EN 206, IS 9142).